Selector valve mechanism



Aug. 12, 1947. c. BiLIVERS SELECTOR VALVE MECHANISM 4'Sheets-Sheet 1 Filed June 19, 1943 0'0 3 6 n5 I Gv-sliLa i/e21: WM W m;

1947. c. B. LIVERS 2,425,380

WHIUHIJ SELECTOR VALVE MECHANISL:

' Filed June 19, 1943 4 sheets -sheet 2 Y "60 n61 I y I w w I 5 I 1 5x Aug. 12, 1947. c. B. LIVERS 2,425,330

SELECTOR VALVE MECHANISM Filed June 19, 1943 4 Sheets-Sheet 3 0&4,

Patented Aug. 12, 1947 sarno'roa VALVE MECHANISM Carlos B. Livers, San Diego, Calif., asslgnor to Consolidated Vultee Aircraft Corporation, San Diego, Calif., a corporation of Delaware Application June 19, 1943, Serial No. 491,430

2 Claims. 1

The invention relates to valve mechanism for selectively controlling'the two-way operation of hydraulically operable systems or devices'and is adapted more particularly for use in aircraft in which such systems or devices are used for 2 Fig. 1 is a front elevation of selector valve anism embodying the invention.

Fig. 2 isa horizontal section taken on line 22 mechof Fig. 1.

raising and lowering the landing gear, opening and closing bomb-bay doors, extending and retracting landing flaps, and for other purposes.

The several objects of the invention are to provide an improved selectively controllable valve mechanism: which is constructed and arranged so that any leakage past the valves in one unit of the selector mechanism cannot cause malfunctioning of the valves of another unit; which vents off or exhausts the fluid through a return valve in the selector mechanism, when thermal expansion causes the fluid in' the lines between the selector mechanism and the operated devices to volumetrically increase; in which each control member is automatically returned to neutral position as soon as the hydraulically operable device has completed its movement for either of the two-way operations so that the pressure in Fig. 3 is a sectional transverse section'taken on line 3-3 of Fig. 2 showing one control valve mechanism in its normal position in which it cuts off the flow of fluid to and from a hydraulically operable device.

Fig. 4 is a vertical longitudinal section taken on line 44 of Fig. 3.

Fig. 5 is a view similar to Fig. 3 illustrating one control valve mechanism in the position assumed when fluid is being forced to and returned from a two-way connection for a hydraulically operable device.

Fig. 6 is a section taken on line 66 of Fig. -2. Fig. 7 is a vertical section illustrating one of thepilot rods, and the ducts for fluid controlled the lines of tubing will drop to zero and each pipe are automatically returned to neutral position as soon as the hydraulic device has performed either of its two-way functions so that the lines'arenot pressure stressed except during the brief intervals necessary for the actual operation of the device;

by the rod, the rod being shown in its normal v or neutral position. 1

Fig. 8 is a plan view of one of the sleeves for a pilot rod.

- Fig. 9 is a horizontal section taken on line 99 of Fig. 7, the pilot rod being shown in elevation. Fig. 10 is a plan view of the pilot rod sleeve which is connected to the port in the casing through which by-pass fluid flows to one of the in which the actuating valves of the selectors are of the open-center type so that an unloading where it can be protected by armor plate without increasing its dead weight load,'an d is adapted for electric remote control operation; in which the casing is of sectional construction so'that the number of units in the selector mechanism may be increased or decreased according to the number of hydraulically operable devices which'are tobe controlled; which issimple in construction and efllcient in operation. Other objects will appear from the detailed description.

' The invention consist in the several novel features: whichare hereinafter set forth and more particularly defined by claims at the conclusion hereof. y a ii In the drawings:

which is equipped with valves for individually controlling the flow of fluid, such as a suitable .oil, for the actuation of a two-way hydraulic system. Any desired number of these units may be used for selective control of a corresponding number of two-way hydraulicsystems. The invention is usable for the selective control of twoway pipe lines for hydraulically operable or controldevices,such as are used in aircraft to raise and lower the landing gear, to open and close bomb-bay doors, for shifting landing flaps and for hydraulically operable devices used for other purposes. These devices may bev of any suitable vconstruction andusually include two pipe-line connections between the casing of the selector mechanism and the fluid-operable devices, which arewell understood in the art, and therefore only the couplings M, F in the casing forsaid connections havejbeenillustrated.

ermined pressureyin the cas- The 'selectord'mechanism comp e a s which is connected to continuously receive fluidunder pressure directly from a pump, or other helpumpto a reservoir while ing when the hydraulically operable devices are nections from the pump to the selector casing for fluid under pressure and the return fluid from the casing to the reservoir from which the pump is supplied are well understood in the art, and therefore only the coupling 24 which is connected to receive fluid under pressure from the pump, the coupling 29 for the connection which returns the fluid circulated through the casing when the hydraulic systems are inactive, and the coupling 21 which is also connected to the reservoir for the return fluid received by the casing from the hydraulically operable devices, are illustrated.

The casing for the selector mechanism is preferably built up of an end-section 29, an opposite end-section .22, and a seriesof intermediate sections 2|. Each of the sections 20 and 2| is equipped with valves and control means of like construction, for selectively controlling one of the hydraulic systems. The side faces of all of said sections flt together in fluid-tight relation and are secured together in series by a series of through bolts 23. This sectional construction makes it possible to readily assemble units for any desired number of hydraulic systems by increase or diminution of the number of intermediate sections and is advantageous in removal and replacement for repair.

Coupling-nipple 24 for the connection to a fluid pump or other constant source of fluid under pressure, is screw-threaded into the casing-section 20 and communicates with and delivers fluid into a longitudinal cylindrical duct 25 (Fig. 4) which extends through end-section 20 and all of the intermediate sections 2| and to a chamber 25 in the end section 22. This duct 25 communicates with the valve-chambers in sections 29 and 2| for the delivery of actuating fluid via the valve-chambers in said sections, to the couplings 44, 44 Coupling-nipple ,2? is screw-threaded into the end-section, and communicates with a 34 by a spring 49 confined in the lower end of piston 33. The upper end of sleeve 38 is cut away to permit fluid to pass through stem 32 into the cross duct 39 which is connected to the outlet coupling 29. When the valves for controlling the connections between the selector casing and the hydraulically operable devices are closed, the spring-loaded valve 34, 35 will maintain a Predetermined pressure of the fluid in duct 25 and permit the excess to flow through the cross duct 39 and coupling 29 back to the reservoir.

- maintaining a predetermined pressure of actu-' g wth a pair of vertically extending parallel cylinlongitudinally extending duct 28 which extends through and communicates with the valve-chambers in end-section .29 and all of the intermediate sections 2| for the return of fluid from the pipe line connections via the valve-chambers in said sections to the reservoir. Coupling 29 is screw threaded into the back of end-section 22 of the casing, .,and the fluid during its circulation through the casing while the control valves are closed, passes through said coupling to the reservoir.

The chamber 26 in the casing-section 22, which communicates with longitudinal pressure duct 25,

I v intersectsand communicates with a cylindrical chamber 30in said casing-section.

The upper end of chamber 39 is closed by a screw-threaded cap ill-which is provided with a hollow and opensided depending stem which is provided on its lower end with an annulus 33 which fits in the chamber 30 below the duct 25. A spring-loaded valve-member 35 is adapted to close'against the seat 34. Valve-member 35 controls the flow of fluid from'chamber 39 to cross duct 39 (Fig. 6) which communicates with .the coupling 29. Valve-member 35 is on and slidably guided by a piston ;36:which is fitted in a cylinder in the sleeve 38 which is flxed in the lower end of chamber 39. Valve-member 35 is urged against its seat inder.

-- ders 43, 43 atthe front and rear of the longitudinal ducts 25 and 28, respectively. The upper portion of each of said cylinders is intersected by and in communication with the longitudinal pressure duct .25. The lower portion of each of the cylinders 43, 43 is intersected by and in communication with the longitudinal return duct 28. A coupling-nipple 44 is screw-threaded into the upper end of each cylinder 43 and a coupling 44 is screw-threaded into each cylinder 43. The couplings 44, 44 on each casing-section serve as means for connection, respectively, to the pipe lines of a pair for the two-way operation of a hydraulically operable device.

Each of the cylinders 43, 43 contains an upper valve for controlling the flow of actuating fluid from duct 25 to the couplings 44, 44, respectively, and a lower valve for controlling the return fluid, which passes through the associated upper valve, into the longitudinal return duct 29 via the lower portion of said cylinders. The valves in each pair of cylinders are alike in construction and operation and are adapted to function alternately to control the flow of actuating fluid to one and return fluid from the other of a pair of pipe connection between one section of the casing and one of the hydraulically operable devices.

The upper valve in each of the cylinders, 43, 43 comprises a slidable valve-member 45 having a hollow depending stem 41, and a seat 46 for said member, which is flxed in the upper end of the surrounding cylinder, for controlling the outflow of actuating fluid from each of said cylinders, respectively. A piston 48, which is screw-threaded to the lower end ofthe hollow stem 47 on each member 45, flts and is slidable in the surrounding cylinder. Fixed stops 59 limit the upper movement of each valve member 45. Each valve member 45 controls'the flow of actuating fluid from duct 25 via the upper portion of its surrounding cylinder to the coupling connected to said cyl- Thehollow stem 41' permits return fluid to pass through piston 48. A spring 49 between seat ring 46 and piston 48 normally presseseach upper valve member 45 closed against its seat 46.

The lower valve in each of the cylinders 43,

' 43 comprises a member 52 which is adapted to the piston 55 and the lower end of stem 54 to normally lift member 52 in the sleeve 55 R on piston 55, for closing member-52 against its seat 5|. The upper end of the cylindrical stem 55 on each piston 55 is provided with lugs by which it This exemplifies means in the selector-casing for is guided in the surrounding cylinder and its lower end is provided with vents 55 to permit fluid to exhaust from the socket in which stem 54 is slidable when said stem is lowered in said piston. Normally, the forc of spring 49 and the pressure oi. fluid against the upper end 01' piston 48 hold the valve member 52 closed and the piston 48 lowered. Normally, each valve member 45 is closed against seat 48 by the pressure of fluid against the upper end of its piston 48 and spring 49. Piston 55 is seated against the lower end of its surrounding cylinder, and spring 53 is eflective to close valve-member 52 against its seat 5I, as illustrated in Fig. 3. With both of the actuating valves and return valves closed, the fluid in the pressure duct 25 will be kept under predetermined pressure by the valve 35, 34, in casingsection 22 and the excess fluid will be returned around member 35 and through duct 39 and coupling 29 to the reservoir. Each'valve 52, 5I functions to'control the flow of return fluid which passes through the hollow stem 41 o! the actuating valve above it, and the lower portion of the surrounding cylinder 43, 43 to the longitudinal return duct 28 for return to the reservoir.

Each piston 55 is shiftable by fluid under pres sure delivered into the lower end of its surrounding cylinder by control means hereinafter described, to open the upper valve for controlling the delivery of actuating fluid to one of the pipe connections.

The area of the upper end of each piston 48 is greater than the exposed area of the under side of valve member 45 so that there will be a preponderating pressure for moving the piston 48 downwardly to close valve member 45 and nor-.- mally hold the actuating valve closed. When the piston 55 of the lower valve is raised by fluid under pressure in the lower end of its cylinder, the actuating valve is positively opened and held open by the abutting engagement of the upper end of the hollow stem 55 of piston 55, valve-member 52 and seat 5| on piston 48 (cylinder 43 in Fig. 5). When the member 45 of the actuating valve is closed, the return fluid passes through stem 41 and unseats valve member 52 (cylinder 43 in Fig. 5).

When both actuating "and return valves are closed, as illustrated in Fig. 3, there will be no fluid under pressure in the lower ends of cylinders 43, 43 for lifting the pistons 55. The opening of one of each pair of upper valves for the outflow of actuating fluid is controlled by fluid under pressure acting against the lower face of a piston 55 while'the other of said upper valves remains closed, so that the return fluid will flow through the stem 41 of the latter valve and unseat valve member 52 to permit the return fluid to flow to the return duct 28.

The means for selectively controlling fluid to and from each associated pair of cylinders 43, 43 for the control of the valves therein comprises a. pilot rod or valve-member 8,0 which is slidably mounted in a fixed sleeve iii. A rod 80 and a sleeve 5| are provided in each of the casing-sections and 2I. Each rod 80 controls the flow oi fluid to and from the lower ends or one pair of cylinders 43, 43 for operating the pistons 55. Each pilot rod is normally held in a centralized position (Fig. 3) by a coil spring I 05 which is confined in a sleeve I08 which pro- :lects from one of the casing-sections. Each pilot rod 80 is shittable forwardly from its neutral position to control one or the upper valves in the cylinders 43 for the outflow of actuating fluid from duct 25 to coupling 44 while thereturn fluid which enters the casing through coupling 44' flows via duct 28 to the reservoir. Each pilot rod 80 is also shiftable rearwardly from its neutral positionto control the upper valve in the cylinder 43* for the outflow or actuating fluid through coupling 44- while the return fluid which enters the casing through coupling 44 flows via duct 28 tothe reservoir. A spring I05 is confined between washers I01 and I08 on each rod 80, and normally engages a shoulder I09 on leeve I08 and a ring H0 fixed in said sleeve, respectively. The stem 80' of rod 80 has an abutment II I for compressing the spring I05 when rod 80 is moved forwardly while washer I01 engages shoulder I09. Said stem 80 also carries a nut III for engaging washer I01 and compressing the spring while washer I08 engages ring IIO when the rod 80 is moved rearwardly. This construction permits each of the rods 60 to be shifted in either direction from its neutral position to selectively control, by fluid under pressure, the upper valves in the cylinders 43, 43 and causes each rod 80 to be returned to its neutral position at the conclusion of each operation. Each rod 80 is held in either of its shifted positions by electric control mechanism hereinafter described and automatically released at the end of an actuating operation.

Each pilot rod 80 has a cylindrical periphery fitting in the bore of a sleeve 8| and is provided with annular grooves 82, 83 and 84. A vertical port 89 connects the lower end of each cylinder 43 with the bore of a sleeve 8|. A port 89 connects the lower end of each cylinder 43* with the bore of a sleeve 8I. Each annular groove 82 and the cylindrical portions of rod 80 at the ends of said groove, control the flow of fluid via port 89 to and from the lower end of a cylinder 43. Each annular groove 84 and the associated cylindrical portions of rod 80 at the ends of said groove, control the flow oi fluid via port 89 to and from the lower end of cylinder 43. The annular groove 83 and the portions of rod 80 -ad- Jacent its ends, permit the return of fluid to the longitudinal return duct 28, when the actuating and return valves are in their normal position.

A restricted flow of fluid from the upper portion of cylinder 30, which communicates with the pressure duct 28 in casing-section 22 (Fig.

' 6), is used for shifting, under control of the pilot rods 80, the pistons in the lower ends of cyltons 55. This fluid passes through a nipple H and a strainer 12 which are secured in the upper endof valve member 35. The flxed sleeve 38 in which the piston 38 on valve member 35 is slidable, has cut-away portions in its lower end, to permit the fluid to pass to the cross duct 10.

Duct extends longitudinally of the casing, receives fluid from cross duct 10, and is connected by a port 84 to the bore of each or the sleeves 8|, for supplying fluid under pressure to the lower endof each of the'cylinders 43; duct 88' extends longitudinally of the casing, receives fluid from cross duct 10 and is connected to each of the sleeves -8I by a port 85, for supplying fluid under pressure to the lower end of the cylinders'll A longitudinal duct 41 is connected by a port 91 to each of the sleeves 6|, for exhausting fluid from the cylinders 43, and a longitudinally extending duct 61* is connected by a port 91 to each of the sleeves 6!, for exhausting 'fluid from the cylinders 48 The end of the longitudinal exhaust ducts 61, 61' are connected, in casingsection 22, by diagonal ports I82 to a recess I84 which communicates with one end of the return duct 28.- A

Each sleeve 6| is provided on its outer periphery with a longitudinal channel 86 which is in communication with a port 84, an annular groove 81 communicating with channel 86, and a series of radial ports 88 which, when said radial ports are. unblocked by the forward movement of the rod 68 from its neutral position, permit fluid under pressure to flow from longitudinal duct 65, via port 84, channel 86, ports 88, annular groove 62 in rod 68, and port 89 to the lower end of cylinder 48 for lifting'the piston 55 therein. Each sleeve 6| is also provided with a longitudinal channel 98, an annular groove 92 and radial ports 9| which, when they are unblocked by the rearward movement of the pilot md 68 from its neutral position, will permit fluid under pressure to flow from duct 65', via port 85, channel 98, groove 92, radial ports 9|, the annular'groove 64 in rod 68, and port 89*, to the lower end of a cylinder 43*,

Each sleeve 6| is also provided with a longitudinally extending channel 96, an annular groove 95 and radial ports 94, which when the rod 68 is in its neutral position (Fig, 'I) will permit fluid in the lower end of cylinder 43 to exhaust via port 89, channel 62 in rod 68, radial ports 94. annular groove 95, longitudinal channel 96,-

and port 91, to the longitudinal return duct 61. When rod 68 is moved forwardly from its neutral position it will block the exhaust from cylinder- 43 at the radial ports 94. Each sleeve 6| is also provided with a longitudinal channel I88, 'an annular groove 99, and radial ports 98 which, when the rod 68 is in its neutral position, will permit. fluid from cylinder 43 to exhaust'via port 89, channel 64 in rod 68, radial ports 98, annular groove 99, longitudinal channel I88, and ports 91* to the longitudinal return duct 61.

, fluid under pressure will flow from duct 65 into the lower end of cylinder 43 to raise the piston 55 therein. When the pilot rod 68 has been thus shifted, radial ports 98 will remain unblocked by the rod for the exhaust of fluid from the lower end of cylinder 43 to longitudinal return duct 61.

When the pilot rod 68 is shifted inwardly or rearwardly it will unblock the radial ports 9| so that fluid under pressure will flow from longitudinal duct 65 to the lower end of cylinder 43 and simultaneously block the radial ports 98 to prevent exhaust of the fluid from said cylinder to longitudinal return duct 61. In this shifted position of pilot rod 68, the exhaust connection from the lower end of cylinder 43 to return duct 61 will remain open.

8 Fluid which is bit-Passed in restricted volume from that under pr ure in cylindrical chamber 88 in casing-section 2, flows via duct 18 to the longitudinal ducts 651% for shifting the pistons 55 in cylinders 49, 43 The :by-pass fluid also flows from duct 18 into a duct 13 which extends longitudinally through the casing-sections 2|, is

intersected by the flxed sleeves 6|, and terminates at one side of the sleeve 6| in the casingsection 28.

The sleeves 6| in the casing-sections 28, 2| are adapted to permit the fluid in duct 18 to flow to the return duct 28, when the pilot rods are in their neutral position, The sleeves in each section 2| are provided for this purpose with a longitudinal channel 15 which communicates with the duct 13 at one side of the sleeve, an'annular groove 16, radial ports 11, which communicate with the annular groove 63 in rod 68, radial ports 18, an annular groove 19, and a longitudinally extending channel 88 on the opposite side of the sleeve which communicates with the continuation of the duct 13. The sleeve 6| in casing-section 28 is similarly provided with a channel 15, groove 16, radial ports 11, 18, an annular groove 19, and a longitudinally extending channel 8| (Fig. 10)

which communicates with a vertical port 14 (Fig. 4) through which the fluid can flow into the iongitudinal return duct '28. When the pilot rods are in their neutral position, the fluid from orifice 69 will flow into the end of duct 18 in the casing- .section 22 successively through the channel grooves and ports in the sleeves 6|, the associated grooves 83 in the pilot rods, to the duct 14 to the return duct 28. When one of the pilot rods 68 is shifted, either forwar 1y or backwardly from its neutral position, it will block the flow of the by-pass fluid to the return duct 14 by blocking the radial ports 11 or 18, respectively. This blocking will create a back pressure in the sections of the duct '13 between the shifted pilot rod and the casing-section 22 and in the longitudinal ducts 65, 65 for the operation of pistons 55.

While all of the pilot rods are in their neutral position, the flow of the fluid in longitudinal ducts 65, to cylinders 43 is blocked at the radial ports 88, and to cylinders 43 at the radial ports 9|; the lower end of cylinder 43 can exhaust through ports 89, radial ports 94, groove 95, channel 96, port 91, and exhaust duct 61; and fluid in the lower end of cylinder 43 can exhaust through ports 89, radial ports 98, groove 99, channel I88, port 91, and exhaust duct 61.

When a pilot rod 68 is shifted forwardly or to the right, it will block the flow of fluid in the duct 13 to the return duct 28 at the radial ports 62 in the pilot rod, and port 89 to the lower end of cylinder 43 for opening the actuating valve in said cylinder; block the flow of fluid from duct 65 to cylinder 43 at the radial port 9|; and leave the lower end of the cylinder 43* open to exhaust through port 89, groove 64 in rod 68, radial ports 98, groove 99, channel I88, and port 91 to duct 61.

ducts 65 and 65"; block the exhaustof fluid from cylinder 43 at radial ports 98; permit fluid under pressure toflow from duct 65'- through a port 85,

channel 90, groove 92, radial ports SI, groove 64 in the pilot rod, and port 89"to the lower end of cylinder 43 for opening the actuating valve in said cylinder; block the flow of fluid from duct Git-to cylinder 43 at the radial port 88; and leave the lower end of the cylinder 43 open to exhaust either of the two-way operations of the hydraulic,

system and discontinue the delivery oi! actuating fluid under pressure to said system, and the pipe lines will not be kept under actuating pressure after the device has been shifted to either of its alternate positions. Each pilot rod 60 is shiftable inwardly and outwardly from its neutral positlon, respectively, by suitably wound' shifting coils H2, H3 of a solenoid magnet, the armature II4 of which is operatively connected to the rear end of the stem 60 of the rod. While the coil I I2 is energized it will hold the armature I I4 and I the pilot rod 60 outwardly or forwardly for control of the valves in the casing-section in which the shifted pilot rod is mounted, to deliver fluid under pressure to one of the cylinders 43 from duct 25 to and through the coupling 44 and simultaneously control the flow of the return oil fromthe coupling .44 via cylinder 43, to the return duct 28. When the coil I I3 is energized, the pilot rod 60 connected thereto will be shifted rearwardly and there held to control the valves in that casing-section in which the pilot rod is mounted, so that fluid under pressure will flow from duct 25 to and through coupling 44" and return fluid can pass from coupling 44 to the return duct 28. Means are provided for interrupting the circuits for holding coils H2, 3 as soon as the hydraulically operable system has completed either of its two-way functions. A manually operable switch lever I I 5 is provided for controlling the movements of each pilot rod 60 by the coils H2, H3. Each lever ll5is normally held in its centralized or neutral-position by a spring I I6 and is shiftable to selectively close circuitsfor the two-way operation of. the hydraulic device for completing its function in either direction. The means for thus controlling the coils I I2, I I3 comprises a battery I I! which has one of its poles connected to contacts H8 and IIS and its other pole connected for energizing the coils H2 and H3; a pair of contacts I20, I2I engageable by the lever I I5 for closing a circuit from the battery to energize the coils I I2 and H3; an electromagnet I24 for holding the lever II5 engaged with contacts II8, I20 and which iscontrolled by a limit-switch I26 which is associated-with the hydraulically operable device and operable at the end of a one-way actuation, and an electromagnet I25 for holding the lever II5 engaged with cone I3 and successively through all of the sleeves 6I tacts IIS, I2I, for energizing the coil II3 which is controlled by a limit switch I21 associatedwith and operable at the, end of the other. actuationby the hydraulically operable device. When the lever II5 has been shifted to; energize coil I: 'I2,'--. holding coil I24 will hold ,the'jlever'to keep the circuit for said coil closed until I26 is opened. When lever I15 1 1'2! until the limit switch-.121 is pjen shift the lever I I5 .to its neutral position sogthat i fi d c S the g'circuit fonshiftingcoilx-II3, he'ljeyer' will-be held to close the circuit for'sai cally operable devices are relieved of the stresses of "actuating pressure except during the brief periods in which the shifting of said devices occurs. In practice it is advantageous to place the selector in a. relatively invulnerable location on the airplane where it is'least exposed to gunfire. The

' electrical control for the pilotrods may be remotely located from the selector within reach of the pilot. A handle I28 is connected to the front end of each pilot rod 60 so that it can be manually shifted in the event that the electric control for the pilot rodshould fail or become inoperative.

The operation or each of the units of the se- 1 lector for controlling the two-way operation of one of the hydraulically operable devices will be the same.

The operation of each unit will be as follows: Normally, the pilot rods 68 are spring-held in their centralized position, the valve members 45 and 52 in both of the cylinders 43, 43' in each of the casing-sections 20 and 2| will be closed, as illustrated in Fig. 3, and the residual fluid will be retained, without actuating pressure, in the pipes connected to. the couplings 44, 44. Fluid will be constantly delivered by the pump, through coupling 24 into the longitudinal duct 25 and the upper portions of the c linders 43, 43". Valve members 45 in both cylinders 43, 43 will be held I closed by springs 49. Naive members 52 will be held closed by springs 53. No fluid from pressure duct 25 willthen flow to the couplings 44, 44 or through the cylinders 43, 43 to the return duct 28. A relatively low predetermined pressurewill be maintained in duct 25 an the upperportion of cylinders 43, 43 by the spring-loaded valve member 35 in the casing-section 22. The excess fluid will flow from cylindrical chamber 30 in casing-section 22, around valve member 35, and

through cross-duct 39, to the coupling 29 which pilot rods 60. The flow or fluid from duct 65- to cylinders 43 will then be blocked at radial ports 9| by the pilot rods 60 so that there will be no pressure acting on the pistons 55 in the lower ends of cylinders 43, 43*.v From cross-duct Ill in casing-section 22 some of the fluid from oriflce 69 will also flow into the longitudina1.duct

and grooves 63 in the pilot rods 60 to the longitudinal channel 8| in the sleeve 6| in casing-section 20, from which it will be returned through duct '14, the return duct 28 and coupling 21 to the reservoir, The lower end of cylinders 43 will be open for the exhaust of fluid throughports 89, annular grooves 62 in th pilot rods, radial ports 34, channels 96, ports 91, and one of the diagonal ports I02 in casing-section22, chamber I04 and the return duct 28; The lower end of the cylinders43! will be open to exhaust fluid through ports .89", grooves 64 in rodsflhradial ports 98," annular groove 89, longitudinal channels I00, Portsfl'. ducts-61, one crthediagonal II 3, I28 and I23. A circuit will be established from battery II1 through coil II2, contact I28, switch lever H and contact 3 for energizing said coil and holding the pilot rod 58 in its outward or forward position. The energized holding coil I24 will retain switch lever H5 in its closed position until the limit-switch I23 is opened at the completion of the one-way shifting operation of the hydraulically controlled device.

This outward movement of pilot rod 68 will block the fluid from oriflce 69 in piston 33, at radial ports 11 in sleeve 6| at the shifted pilot rod and prevent the return of said fluid through the continuation of duct 13 and port 14 to the return duct 23 which will cause a back pressure to be produced in the chamber 33 below pistonv 35, forcing the latter upwardly until the valve 35 seats. Valve 35 is thereafter held against its seat 34 by the differential hydraulic pressure resulating from the fact that the cross-sectional area of the piston 33 which is acted upon by the fluid in the bottom of the chamber 38 is greater than the area of the valve 35 which is acted upon by the fluid in the top of the chamber 38. The I closing of the valve 35 causes the pressure in the top of chamber 30 and in the passageway 25 to build up almost instantly to the full operating pressure of the system. At the same time. the pressure in the bottom of the chamber 38 and in passageways 13, 65 and I55 is also built up to the full operating pressure by reason of the passageway a the pressure in the return fluid passing through coupling 44 is discontinued. spring 53 will be blocked at radial ports 33. Spring 48 and the pressure against piston 43 will close the actuating valve which was opened, and as soon will close valve member 52 against its seat 5|. Both of the actuating valves and the return valves will then be closed as illustrated in Fig. 3 and will remain closed until one of the pilot rods' is operated. The by-Pass fluid in the duct 13 will then flow successively around the sleeve 3I to port 14 and the return longitudinal duct 23.

When the hydraulically operable device is to be reversely shifted. the pilot will shift the switch lever H5 to engage contacts H8, I2I and I22 which will establish a circuit for energizing the coil I I3 and holding coil I25 which will hold said lever in its shifted position until the limit-switch 69 in piston 36. The flow of fluid from the duct 65' to cylinder 43 is then blocked at the radial ports 9| by the shifted pilot rod to prevent fluid under pressure from passing into the lower end of cylinder 43. The lower end of cylinder 43 remains open to exhaust via radial ports 33, annular groove 89, channel I38, port 81, and duct valve member 52 against its seat 5| and lift piston 48 and its stem 41 to open the valve member 45. Fluid under pressure from duct 25 will then I flow around stem 41 and valve member 45 to the coupling 44 for delivering actuatin fluid for oneway operation of the hydraulic device. The valve member 45 in the cylinder 43 will be held closed by its spring 49 and fluid pressure against the upper end of its piston 43. The piston in the cylinder 43 will remain lowered and the return fluid entering the casing through coupling 44 from the hydraulic device flowing through the hollow stem 41 will open the valve member 52 and permit the return fluid to flow into the lower portion of the cylinder 43 to the return duct 23.

When the device has been hydraulically shifted by actuating fluid from coupling 44, the limitswitch I23 will be opened 'by or under control of the device, and open the circuit through the holding coil I24 so that lever "-5 will be free to be shifted to its neutral position by the spring 5. The spring I05 will then return the pilot rod functioning and so that the volumetric increase of the fluid in the lines between the selector valve which has been shifted to its neutral position.

The return of the pilot rod to its llt lll lal position I21 is opened b the hydraulic device. The coil I I3 will shift the pilot rod 38 inwardly, which will block the flow of 'by-pass fluid in the longitudinal duct .at the radial ports 83 and cause a back pressure to be built up in the longitudinal duct 65 will block radial ports 33 to prevent exhaust from cylinder 43; will unblock the radial ports 9| so that fluid under pressure will flow from duct 65' through port 35. channel 88, groove 82,

radial ports 9|. channel 34, and port 38 into the lower end of the cylinder 43'- to shift piston 55 and open the valve member 45' to shift piston 55 and open the valve member 45 in said cylinder 43 for the flow of actuating fluid through coupling 44 for the reverse operation of the hydraulic system; and will block radial ports 33 to prevent flow from longitudinal duct 35 to the cylinder 43. The valve 45, 43 in cylinder 43 will then function to deliver'actuating fluid through coupling 44 to the hydraulic system, and the valves in the cylinder 43 will function to deliver the fluid returned from the system through coupling 44 to the duct 23. When the hydraulic device has completed its reverse operation. the limit-switch I21 will be opened to interrupt the circuit through the holding coil I25 and switch lever II5 will be released for shift to its normal position by the spring I13. Coil II3 will then be deenergized and the spring Ill-5 will restore the shifted pilot rod to its neutral position which will cause the valves in both of the cylinders 43 and 43 to be restored to normal position as before described, to retain the fluid'in both p pe lines of the two-way connection, and to cause the fluid to be circulated through the, casing and the coupling 28 to the reservoir. as before described.

The invention-exemplifies selector valve mechanism which is constructed and arranged so that any leakage past the valves will not impair its mechanism and the hydraulically operable device due to thermal expansionis vented off through return valves in the casing. In the'event of leak; age past the valves either during operation of the shifting mechanism orcaused by volumetricincrease of the fluid inthe lines due jto,thern:ial T xpansion, .it passes around one of'the return 2,42s,-sso

13 valv members 52 into the passages for returning the fluid to the reservoir.

The invention exemplifies control mechanism for the pilot rods which is automatically reset to ,neutral position at the end of each actuating operation independently of the operator or pilot and it is impossible to leave the hydraulically operable system in on or off position after each shifting operation has been completed. This reduces the periods during which the tubing between the valve mechanism and the hydraulically operable device is subjected to actuating pressure stresses which may frequently cause pre mature failure of the lines, and reduces the stresses to the brief periods of the shifting Operations.

The invention also exemplifies selector mechanism in which the circulation of the operating fluid under predetermined pressure through the valve casing is controlled by a spring-loaded valve in theend section 22 of the casing, which makes in which'pilot rods or pistons and the ducts con-- trolled thereby described render their shift exceptionally easy because they merely control the flow of by-passed fluid and do not necessitate sufllcient force to overcome the fluid pressure. This renders it possible to manipulate the controls electromagnetically or manually with flnger-tip ease. In hydraulic systems used in aircraft, the pressure sometimes exceeds 2000'lbs. per square inch.

The invention exemplifies a construction in which each of the intermediate casing sections and the valve mechanism therein constitute a unit for the selective two-way operation of a hydraulically operative device. Sections II are identical in construction and the inlet and outlet couplings 24 and 21 are connected to the endsection 20 and the returncoupling 28 is connected to the opposite end section 22 which contains the pressure controlling valve. This makes it possible to assemble any desired number of intermediate tially parallel pressure and return ducts extending through the casing section between and communicatively intersecting the cylindrical chambers, a slidable piston and valve in each cylindrical chamber for controlling the flow of actuating fluid from the pressure duct to the respective system, a slidable valve and piston in each of the cylindrical chambers for controlling the flow of fluid from said system to the return duct, means for conducting fluid from the pressure duct to each of the cylindrical chambers, means for conducting fluid from each of the cylindrical chambers to the return duct, a pilot valve in the easing movable between a neutral position and two actuating positions and being provided with means for controlling flow through each of said fluid conducting means, a by-pass through the casing for fluid from the first-mentioned fluid conducting means, and means controlled by the' pilot valve for opening said by-pass when the pilot valve is in neutral position and for closing the by-pass and building up pressure in the fluid to the pilot valve when the pilot valve is shifted to an actuating position.

2. Mechanism for selectively and hydraulically controlling a plurality of two-way hydraulic systems, comprising: a plurality of like units for individually controlling the systems, respectively,

'each unit comprising a casing section adapted to mate with the casing section of another unit, a pair of parallel cylindrical chambers, substantially parallel pressure and return ducts extending through the casing section between and communicatively intersecting the cylindrical chambers, a slidable piston and valve in each cylindrical chamber for controlling the flow of actuating fluid from the pressure duct to the respective system, a piston in each cylindrical chamber carrying a spring-pressed valve and piston in each of the cylindrical chambers for controlling the flow of fluid from said system to the returnduct, means for conducting fluid from the pressure duct to each of the cylindrical chambers,

units between the end-sections. The number of units between the end sections 20 and 22 may be extended to provide for the control of any desired number of hydraulically operable devices on an airplane and units can be readily substituted in the event repair is necessary any of the sections. The handles I20 in the pilot rods make it 0 possible to control the selector valve mechanism in the event that the automatic control becomes inoperative.

The invention exemplifies selector mechanism which is compact, and adapted for electrical remote control so that it can be located in a relatively invulnerable position. on the airplane or can be protected by armor plate without unduly increasing the dead weight load.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

1. Mechanism for selectively and hydraulically controlling a plurality of two-way hydraulic systems, comprising: a plurality of like units for individually controlling the systems, respectively, each unit comprising a casing section adapted to mate with the casing section of another unit, a pair of parallel cylindrical chambers,'su stanmeans for conducting fluid from each of the cylindrical chambers to the return duct, 9. pilot valve in the casing movable between a neutral position and two actuating positions and being provided with means for controlling flow through each of said fluid conducting means, a by-pass through the casing for fluid from theflrst-mentioned fluid conducting means, and means controlled by the pilot valve for opening said by-pass when the pilot valve is in neutral position and for closing the by-pass and building up pressurein the fluid to the pilot valve when the pilot valve is shifted to an actuating position.

. I CARLOS B. LIVERS.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Great Britain. Dec. 11, 1939 i 

